Microfabricated alkali metal vapor cells filled with an on-chip dispensing component

This paper presents a microfabrication technique for vapor cells, filled with cesium (Cs), from an on-chip dispensing component. Wafer-level cell fabrication with a Cs dispenser has gained considerable attention for contributing to the high performance of miniaturized atomic devices. However, the large size of the dispenser and released residual gases can be limitations to miniaturization and the stability of atomic vapor. We present a cell structure that overcomes these limitations and offers a single-mask process with typical Si-based microfabrication at the wafer level. The cell consists of an optical cavity connected to a Cs-dispensing component via microchannels. Microfabricated Si grooves with multiple re-entrant microstructures are employed for effective Cs production from cesium azide. In our experiment, Cs was successfully filled in a cell by heating at 330°C for 10 min. The stability of the Cs atomic density in the cell was confirmed over a period of 5 months.